Polishing pad and polishing apparatus

Abstract

A polishing pad enables efficient removal of a polishing product and an “old polishing liquid” remaining on a surface (polishing surface) or in through-holes of a polishing pad. The polishing pad has a polishing surface and a plurality of through-holes extending in the thickness direction, which communicate with each other by communication grooves. The through-holes have a diameter of, e.g., 2 to 5 mm. The aperture ratio of the through-holes is, e.g., 10 to 50% of the surface area of the polishing surface of the polishing pad. The depth of the communication grooves is, e.g., 40 to 60% of the thickness of the polishing pad. The width of the communication grooves is, e.g., 10 to 50% of the diameter of the through-holes.

1 . A polishing pad having a polishing surface and having a plurality of through-holes extending in the thickness direction, said through-holes communicating with each other by communication grooves.  
     
     
         2 . The polishing pad according to  claim 1 , wherein the through-holes have a diameter of 2 to 5 mm.  
     
     
         3 . The polishing pad according to  claim 1 , wherein the aperture ratio of the through-holes is 10 to 50% of the surface area of the polishing surface of the polishing pad.  
     
     
         4 . The polishing pad according to  claim 1 , wherein the depth of the communication grooves is 40 to 60% of the thickness of the polishing pad.  
     
     
         5 . The polishing pad according to  claim 1 , wherein the communication grooves are formed in the reverse surface of the polishing pad from the polishing surface.  
     
     
         6 . The polishing pad according to  claim 1 , wherein the width of the communication grooves is 10 to 50% of the diameter of the through-holes.  
     
     
         7 . The polishing pad according to  claim 1 , wherein the communication grooves are arranged in a concentric pattern, a lattice pattern, an arc pattern, a radial pattern or a spiral pattern, or a combination thereof.  
     
     
         8 . The polishing pad according to  claim 1 , wherein at least one flow passage groove is provided between the communication grooves.  
     
     
         9 . The polishing pad according to  claim 1 , wherein the polishing pad has a hardness (Asker-C) of 60 to 95.  
     
     
         10 . The polishing pad according to  claim 9 , wherein a support layer, having a lower hardness than the polishing pad, is provided on the reverse surface of the polishing pad from the polishing surface.  
     
     
         11 . The polishing pad according to  claim 10 , wherein communication grooves are formed in the support layer.  
     
     
         12 . The polishing pad according to  claim 1 , wherein at least part of the polishing surface has conducting properties.  
     
     
         13 . A polishing apparatus, comprising: 
 a polishing table having a polishing pad and a first electrode which is connected to one pole of a power source and whose surface is covered with the polishing pad, said polishing pad having a plurality of through-holes extending in the thickness direction and communicating with each other by communication grooves;    a top ring for holding a substrate and pressing the substrate against a polishing surface of the polishing pad;    a second electrode, connected to the other pole of the power source, for feeding electricity to the substrate;    a liquid supply section for supplying a liquid to the polishing surface of the polishing pad;    a conditioning section for conditioning the polishing surface of the polishing pad; and    a relative movement mechanical for moving the substrate held by the top ring and the polishing pad relative to each other.    
     
     
         14 . The polishing apparatus according to  claim 13 , wherein the liquid supply section has a plurality of liquid supply orifices.  
     
     
         15 . The polishing apparatus according to  claim 13 , wherein the liquid supply section makes either one of a linear movement, a reciprocating movement, a pivoting movement and a rotational movement or a combination of two or more movements.  
     
     
         16 . A method for conditioning a polishing pad of a polishing apparatus for polishing and removing a metal film and/or a barrier film formed outside interconnect recesses provided in an insulating film formed on a surface of a substrate, comprising carrying out initial conditioning of the polishing pad in the following two steps: 
 the first conditioning step comprising rubbing the polishing pad with a dresser at a pressure of not more than 0.6 psi; and    the second conditioning step comprising polishing a dummy substrate with the polishing pad at a polishing pressure which is higher than a polishing pressure upon polishing of a substrate.    
     
     
         17 . The method for conditioning a polishing pad according to  claim 16 , wherein the polishing pad is used in chemical mechanical polishing.  
     
     
         18 . The method for conditioning a polishing pad according to  claim 16 , wherein the polishing pad is used in electrochemical mechanical polishing.  
     
     
         19 . The method for conditioning a polishing pad according to  claim 16 , wherein the polishing pressure of the polishing pad upon polishing of a substrate is not more than 1.5 psi.  
     
     
         20 . The method for conditioning a polishing pad according to  claim 16 , wherein during polishing of a substrate or during an interval between polishing operations, the polishing pad is further conditioned by rubbing the polishing pad with a dresser at a pressure of not more than 0.6 psi.  
     
     
         21 . The method for conditioning a polishing pad according to  claim 16 , wherein the first conditioning of the polishing pad with the dresser is carried out at a dressing speed of not more than 50 μm/h.  
     
     
         22 . A polishing apparatus, comprising: 
 a polishing table having a first electrode connected to one pole of a power source and holding a polishing pad having a polishing surface of a larger size than a surface to be polished of a substrate;    a top ring for holding the substrate and pressing the substrate against the polishing surface of the polishing pad at a pressure of not more than 1 psi;    a second electrode including at least one electrode member, connected to the other pole of the power source, which is to make contact with a conductive film of the substrate, held by the top ring and being pressed against the polishing surface of the polishing pad, to feed electricity to the conductive film, and a supporting base for floatingly supporting the electrode member by a floating mechanism;    a liquid supply section for supplying a liquid to the polishing surface of the polishing pad;    a conditioning section for conditioning the polishing surface of the polishing pad; and    a relative movement mechanism for moving the substrate held by the top ring and the polishing pad relative to each other.    
     
     
         23 . The polishing apparatus according to  claim 22 , wherein the electrode member is supported by an electrode base.  
     
     
         24 . The polishing apparatus according to  claim 22 , wherein the floating mechanism is adapted to floatingly support the electrode member by the fluid pressure of a fluid which has been filled into a pressure chamber formed between the electrode member and the supporting base and surrounded by an elastic membrane.  
     
     
         25 . The polishing apparatus according to  claim 24 , wherein the floating mechanism is adapted to supply the fluid at a predetermined pressure to the pressure chamber.  
     
     
         26 . The polishing apparatus according to  claim 22 , wherein the second electrode is provided with a stopper for limiting the movement of the electrode member in a direction away from the supporting base and in a direction parallel to the supporting base.  
     
     
         27 . A polishing method comprising: 
 applying a voltage between a first electrode, connected to one pole of a power source and disposed in a polishing table, and a conductive film, formed on a surface of a substrate, to which electricity is fed from an electrode member connected to the other pole of the power source and supported floatingly; and    polishing the conductive film by rubbing it with a polishing surface of a polishing pad mounted to the polishing table while filling the space between the first electrode and the conductive film of the substrate with a liquid.    
     
     
         28 . A dresser having a dressing surface which is to face a polishing surface of a polishing pad and to make sliding contact with the polishing surface for dressing of the polishing surface, wherein first brush bristles and second brush bristles having lower rigidity than the first brush bristles are implanted in the dressing surface.  
     
     
         29 . The dresser according to  claim 28 , wherein the second brush bristles are longer than the first brush bristles.  
     
     
         30 . The dresser according to  claim 28 , wherein one of the first brush bristles and the second brush bristles are arranged in a concentric pattern, a lattice pattern, a radial pattern or a spot-like pattern, or a combination thereof, with the other brush bristles in the background.  
     
     
         31 . A dresser having a dressing surface which is to face a polishing surface of a polishing pad and to make sliding contact with the polishing surface for dressing of the polishing surface, wherein first brush bristles and second brush bristles, both having the same rigidity but having different lengths, are implanted in the dressing surface.  
     
     
         32 . The dresser according to  claim 31 , wherein one of the first brush bristles and the second brush bristles are arranged in a concentric pattern, a lattice pattern, a radial pattern or a spot-like pattern, or a combination thereof, with the other brush bristles in the background.  
     
     
         33 . A dresser having a dressing surface which is to face a polishing surface of a polishing pad and to make sliding contact with the polishing surface for dressing of the polishing surface, wherein the dressing surface comprises a diamond dressing section provided with diamond abrasive grains having a grain count of #100 or higher, and a brush dressing section provided with brush bristles.  
     
     
         34 . The dresser according to  claim 33 , wherein the diamond dressing section is disposed circumferentially outside the brush dressing section.  
     
     
         35 . A polishing apparatus, comprising; 
 a polishing table having a first electrode connected to one pole of a power source, and a polishing pad covering a surface of the first electrode;    a top ring for holding a substrate and pressing the substrate against a polishing surface of the polishing pad;    a second electrode, connected to the other pole of the power source, for feeding electricity to the substrate;    a liquid supply section for supplying a liquid to the polishing surface of the polishing pad;    a dresser having first brush bristles and second brush bristles having lower rigidity than the first brush bristles, for dressing the polishing surface of the polishing pad by bringing the brush bristles into sliding contact with the polishing surface; and    a relative movement mechanism for moving the substrate held by the top ring and the polishing pad relative to each other.    
     
     
         36 . A polishing apparatus, comprising: 
 a polishing table having a first electrode connected to one pole of a power source, and a polishing pad covering a surface of the first electrode;    a top ring for holding a substrate and pressing the substrate against a polishing surface of the polishing pad;    a second electrode, connected to the other pole of the power source, for feeding electricity to the substrate;    a liquid supply section for supplying a liquid to the polishing surface of the polishing pad;    a dresser having first brush bristles and second brush bristles, both having the same rigidity but having different lengths, for dressing the polishing surface of the polishing pad by bringing the brush bristles into sliding contact with the polishing surface; and    a relative movement mechanism for moving the substrate held by the top ring and the polishing pad relative to each other.    
     
     
         37 . A polishing apparatus, comprising: 
 a polishing table having a first electrode connected to one pole of a power source, and a polishing pad covering a surface of the first electrode;    a top ring for holding a substrate and pressing the substrate against a polishing surface of the polishing pad;    a second electrode, connected to the other pole of the power source, for feeding electricity to the substrate;    a liquid supply section for supplying a liquid to the polishing surface of the polishing pad;    a dresser having a diamond dressing section provided with diamond abrasive grains having a grain count of #100 or higher and a brush dressing section provided with brush bristles, for dressing the polishing surface of the polishing pad by bringing the diamond dressing section and the brush dressing section into sliding contact with the polishing surface; and    a relative movement mechanism for moving the substrate held by the top ring and the polishing pad relative to each other.    
     
     
         38 . A method for dressing a polishing pad comprising: 
 carrying out dressing of a polishing surface of a new polishing pad, at the start-up of a polishing apparatus having the new polishing pad, by bringing a dresser, having a diamond dressing section provided with diamond abrasive grains having a grain count of #100 or higher and a brush dressing section provided with brush bristles, into sliding contact with the polishing surface; and    carrying out dressing of the polishing surface of the polishing pad, during polishing of a substrate or during an interval between polishing operations, by bringing a dresser, having first brush bristles and second brush bristles having lower rigidity than the first brush bristles, into sliding contact with the polishing surface.